Apple has reportedly shown continued interest in building solar-powered devices, but the niche market for solar components is said to require more time to mature.

Apple and Samsung are the two companies specifically said to be "evaluating" solar power for their consumer products, according to a report issued on Wednesday by DigiTimes. Both device makers are alleged to have considered including Taiwan-based solar power component makers in their supply chains.

But citing sources in the Taiwan solar component industry, the report said that the niche market needs more time to develop and expand. Mass production of organic photovoltaic cells is said to remain an issue, and higher efficiency products are still being tested in labs and are not ready for mass production.

"The number of solar cells used is less than rooftop solar systems, hence it is unlikely for solar-powered consumer products to form a solid market in the short term," the report said.

Samsung plans to release a solar-powered netbook, the NC215S, this August, a first for the company. The report said that the Samsung netbook utilizes a unique-sized solar cell.

A number of companies are said to be working on organic photovoltaic cells, which provide higher efficiency and are largely made with polyethylene terepthalate, or PET. America's Solarmer and Plextronics, the U.K.'s Konarka, and Japan's Mitsubishi Chemical are all said to be pursuing organic photovoltaic technology.

Over the years in numerous patent applications, Apple has shown interest in adopting solar power in its mobile devices. This January, one such filing described a device with an auxiliary solar cell that would serve as a secondary power source.

Another proposed invention showed an iPod with solar panels placed on both the front and back of the portable media player, giving a large surface area to collect more potential power. Apple's concept would build solar cells of rigid materials, allowing virtually the entire exterior of the device to be covered in solar cells.

And in 2008, the company presented a concept in which it would sandwich solar panels between the LCD and circuit board of a device. In this way, a product could collect energy through its display while maintaining the aesthetics and size of the product.

I will, as an expert in this field, once again point out this simply will not happen. The physics are against you.

In AM1.5 sunlight, what we get over most of the part of the world that has iProducts, you have 1000 watts of power per square meter of space. Conventional solar cells can capture about 15 to 20 percent of that, and the polymer ones talked about here are about half that. Power conversion will drop another 50% of that. So realistically you're looking at maybe 35 watts per square meter.

The iPhone is about 0.05 square meters. That means it's going to collect a few milliwatts of power. That's less that it draws when in sleep mode, and perhaps the same amount of power that you'd get by plugging it in for 2 minutes or so.

Unfortunately I cannot really picture myself leaving say my iPad or iPhone in the sun for a couple hours to charge. Doesn't really pan out as a "good" idea in my mind as the last thing I would want to happen is the direct exposure from the suns light causing any kind of heat damage, moisture, or sunspots to the screen itself.

Luckily I believe companies such as Energizer have the right idea with their inductive charging technology which allows them to "wirelessly charge" a device. Mind you even that technology has flaws, and is not considered "free energy" unless you perhaps power the charging pad with say um? A solar panel.

... Mass production of organic photovoltaic cells is said to remain an issue, and higher efficiency products are still being tested in labs and are not ready for mass production. ...

Speaking as someone who's been around a while ... this exact sentence can be picked out of photovoltaic marketing materials from the 1970's, 80's, and 90's.

Mass production techniques and cell efficiency were the two main problems on the table at the dawn of this technology, and now 40 or more years later they still are. Efficiency has been raised, but not by much and every day we hear of a new "super-effiicent" solar cell that's just around the corner but never actually materialises. I don't mean to imply that solar cells will never be efficient enough or that the technology is totally worthless, but solar power is *always* over-hyped and promoted far beyond it's actual technical merits.

Would it be great to have a bit of extra power for your handheld? Sure.
Will it ever replace charging it with actual electricity? No.
Will it make a significant contribution to the total power requirements of the device? No
Will it save your bacon when you are stuck in the woods and your battery dies? Probably not.

I will, as an expert in this field, once again point out this simply will not happen. The physics are against you.

In AM1.5 sunlight, what we get over most of the part of the world that has iProducts, you have 1000 watts of power per square meter of space. Conventional solar cells can capture about 15 to 20 percent of that, and the polymer ones talked about here are about half that. Power conversion will drop another 50% of that. So realistically you're looking at maybe 35 watts per square meter.

The iPhone is about 0.05 square meters. That means it's going to collect a few milliwatts of power. That's less that it draws when in sleep mode, and perhaps the same amount of power that you'd get by plugging it in for 2 minutes or so.

Why bother?

Well, lets imagine that thin-film amorphous photovoltaics in near future can reach 10 %efficiency (not unrealistic. today they are around 7-9%).

That would give following electric power for the back of an ipad (0.05 M2):

You naysayers are looking at this all wrong. This would not initially be to fully power or even truly charge the device. It would be to offset the consumption of power to make the battery possibly last a while longer. If you can get an extra hour would it be worth it to you?

NoahJ"It is unwise to be too sure of one's own wisdom. It is healthy to be reminded that the strongest might weaken and the wisest might err." - Mahatma Gandhi

Well, ok, lets take this seriously for a moment, after that little blunder of mine.

Let's take xyz001's tech specs for the solar panels for granted. The biggest (wrong) assumption he is making in that maths is that the back of the iPad will be facing directly to the sun (without even considering clouds!). His numbers would support a vision where we wouldn't need to recharge the iPad at all, ever.

Let's make some less crazy assumptions.

Let's assume that it is in fact viable a 2.5w production of power in these panels. This "2.5" is peak power. Mostly you will have your iPad facing down (specially if it is lying around in any desk). This means that in 80% of the time the solar panel is not doing anything. Let's focus then in usage time. When you are using the iPad, you will be facing it with an angle to the floor, inside some building.

Thus the wattage of light coming into the solar panel will not be 1000 watts per meter, but more on the level of 50-200 watts per meter, depending on where you are, what are you facing, etc. This means that the actual production of the panel will be something between 0.1w and 0.5w. 0.5w in 10 hours is 5.0wh, which is one fifth of the entire energy stored in the battery. It means 2 hours ~ of usage.

So, using the most optimistic numbers ever, we have reached 2 hours of more battery life. And you won't be able to recharge it while facing up (while lying on the desk). This is akin to a few tweaks on the battery levels and the CPU usage, etc. so why bother in the first place? Remind yourselves that far from the better numbers, the average will be more like 20-30 minutes of increased battery, i.e., well within error margin.

There is an exception to this. Imagine that there is this magic "smart cover" that is a thin solar panel. You close your iPad with it and it is facing upwards, lying in a desk. Now that's something better, but nevertheless quite useless (if you are lying it on the desk, why not just docking it and charging it WAY faster??).

So I see no point in here. Only when solar panels get just too cheap to matter, and when CPUs and LEDs use just mind-boggingly low wattages will this have any interest (it might already have for e-ink devices though).

The biggest (wrong) assumption he is making in that maths is that the back of the iPad will be facing directly to the sun (without even considering clouds!).

Actually there are transparent organic PV panels that could be used over the screen, any likely implementation of PV for the iPad would take that approach.

As it said in the article
'And in 2008, the company presented a concept in which it would sandwich solar panels between the LCD and circuit board of a device. In this way, a product could collect energy through its display while maintaining the aesthetics and size of the product.'

Well, ok, lets take this seriously for a moment, after that little blunder of mine.

Let's take xyz001's tech specs for the solar panels for granted. The biggest (wrong) assumption he is making in that maths is that the back of the iPad will be facing directly to the sun (without even considering clouds!). His numbers would support a vision where we wouldn't need to recharge the iPad at all, ever.

Let's make some less crazy assumptions.

Let's assume that it is in fact viable a 2.5w production of power in these panels. This "2.5" is peak power. Mostly you will have your iPad facing down (specially if it is lying around in any desk). This means that in 80% of the time the solar panel is not doing anything. Let's focus then in usage time. When you are using the iPad, you will be facing it with an angle to the floor, inside some building.

Thus the wattage of light coming into the solar panel will not be 1000 watts per meter, but more on the level of 50-200 watts per meter, depending on where you are, what are you facing, etc. This means that the actual production of the panel will be something between 0.1w and 0.5w. 0.5w in 10 hours is 5.0wh, which is one fifth of the entire energy stored in the battery. It means 2 hours ~ of usage.

So, using the most optimistic numbers ever, we have reached 2 hours of more battery life. And you won't be able to recharge it while facing up (while lying on the desk). This is akin to a few tweaks on the battery levels and the CPU usage, etc. so why bother in the first place? Remind yourselves that far from the better numbers, the average will be more like 20-30 minutes of increased battery, i.e., well within error margin.

There is an exception to this. Imagine that there is this magic "smart cover" that is a thin solar panel. You close your iPad with it and it is facing upwards, lying in a desk. Now that's something better, but nevertheless quite useless (if you are lying it on the desk, why not just docking it and charging it WAY faster??).

So I see no point in here. Only when solar panels get just too cheap to matter, and when CPUs and LEDs use just mind-boggingly low wattages will this have any interest (it might already have for e-ink devices though).

How many here would love to get an extra 30 minutes to an hour out of their device? Without having to tweak the settings to lower intensity screen or having the screen turn off every 5 seconds? I say put the solar cells in! If you get 30-60 extra minutes out of them, they have accomplished their mission. If you get more then bravo!

NoahJ"It is unwise to be too sure of one's own wisdom. It is healthy to be reminded that the strongest might weaken and the wisest might err." - Mahatma Gandhi

You naysayers are looking at this all wrong. This would not initially be to fully power or even truly charge the device. It would be to offset the consumption of power to make the battery possibly last a while longer. If you can get an extra hour would it be worth it to you?

What if the electronics needed for the charge controller took up room that the battery would use and gave you 1 hour of power? How about then?

Or, more likely, it added $25 wholesale and gave you the same power ad plugging in for 2 minutes?

Apple has spent a lot more effort, money, development time, and sacrificed a lot of features to eke out even 1 hour of battery life from its products.

2 hours (most optimistic, or 1 hour, more realistically) of battery time is enough for them to spend money on. Especially if it can be done without sacrificing performance/features, like they have had to in other efforts to increase battery life.

What if the electronics needed for the charge controller took up room that the battery would use and gave you 1 hour of power? How about then?

Or, more likely, it added $25 wholesale and gave you the same power ad plugging in for 2 minutes?

Then Apple wouldn't use it.

However, if the cost-benefit ratio works out, then they will. I know you mentioned you are an expert in this field, but I am pretty sure there were many experts in the early 1900's who also said we couldn't fly.

SO, let's make some maths. Let's still be *generous* and apply the whole indoors radiation to the iPad's solar panel as if it isn't tilted 45 degrees, if there aren't any hands holding the iPad, etc., most of the times (common methods of determining radiation imply a surface towards the ceiling). While being generous here, we shouldn't forget it.

Total production indoors in an iPad:

.0455 * 1 *10% = 45mW.

Total production outdoors in an iPad facing upwards with no clouds, etc., etc.:

0.0455 * 1350 * 10% = 6.1W.

Total production indoors (with wide windows) in an iPad:

.0455 * 10 *10% = 450mW.

Indoors power production over ten hours = 450mW. A power production that will run your iPad for the staggering ammount of ten minutes.

Outdoors power production over ten hours facing it upwards with no clouds, etc.: a power production that will run your iPad for two hours more.

Indoors with wide windows power production over ten hours = 4.5W. A power production that will run your iPad for reasonable 100 minutes.

Final remarks: You won't be using your iPad outdoors 90%+ of the time. You won't be leaving it outdoors to "recharge" as well. The solar panel is ridiculously useless. There's the extra point that a solar panel inside the LED display will never reach 10% efficiency for obvious engineering reasons.

It may provide ~1 hour of extra battery if left at the desk of a room with wide windows for ten hours. But if you are doing so, why not just plug it for two minutes?

Very well and fair enough. Let's be more rigorous with our numbers then.

How about some rigour with the units? The SI for the watt is W not w. you can't say that 'power production over 10 hours is 450mw' that's just garbage. you mean mWh. What is it about power units and energy units that makes people do such violence to them ?

As to your assumptions. The idea that internal illumination is only 1W/m^2 only makes sense for artificially lit space.

My 40 m^2 living room has about 6 m^2 of windows, so average internal illumination from daylight of order 100W/m^2. Ok, maybe I have more window than average, but still it's going to be more than 10 for daylit space.

How about some rigour with the units? The SI for the watt is W not w. you can't say that 'power production over 10 hours is 450mw' that's just garbage. you mean mWh. What is it about power units and energy units that makes people do such violence to them ?

As to your assumptions. The idea that internal illumination is only 1W/m^2 only makes sense for artificially lit space.

My 40 m^2 living room has about 6 m^2 of windows, so average internal illumination from daylight of order 100W/m^2. Ok, maybe I have more window than average, but still it's going to be more than 10 for daylit space.

Apologize for the unit naming errors in the first post, that of course should have been written correctly. Never the less your posts do kind of acknowledge there would be a substantial gain under certain circumstances. I agree with you however that with current specs the gains could be rather small! My original post was meant to counter Maury Marcowitx so-called expert-on-the-subject post, and still it shows that he was way off talking about a few milliwatts. The technology is certainly relevant!

Notice one thing:

Amorpheous (thin-film) solar cells have very high efficiency when not facing directly towards the sun and/or in cloudy conditions. This is opposed to traditional mono- or poly crystaline PV's that need to be oriented directly towards the sun in order to perform efficiently. And transparent versions are coming, making it possible to mount on the screen.

Lets for fun try to do the calculation in a different way. Most PV products on the market have a yearly production of around 200 Kwh for 1 M2 of panel. Notice these are rough numbers, and they are based on San Diego location. It is not a theoretic number, but a real measurement on the energy bill.

This is during the average daytime of 12 hours. So per hour of daytime this is: 548 watts per day / 12 hours = 45 watts per Hour.

This is for 1 M2, lets see how much for an ipad size of 0.05 M2

45 watts per hour x 0.05 M2 = 2,28 WH per ipad!

This is off course based on a perfect angled, always outdoor ipad. But...it is also an average number from sun-rise to sun-set. You can expect charging at noon would give you much more than 2,28 WH from the PV panel.

Anyway, this was just another completely unscientific way to show that there might be a future in this, when technology improves just a little. If anyone have WattHour specs on a specific PV product it would be easier to discuss!

MP=MR is a program formula used in marketing and movements to demonstrate that each little step, combined with all other little steps produces a significant result that all participants can share in.

Entertain if you will, that it's not necessarily what solar can provide to the individual in terms of personal energy, the inflection point is when you multiply those savings by the number of solar enabled devices in the market (lets say 20 million) and you get a significant and PR worthy amount of energy taken off the grid. A macro result that you can point to and say "I am responsible for that."

Any takers on postulating the math on what that would look like for a day/year on 20 million units? (I don't want to upset the engineers on the board with my math)

Any takers on postulating the math on what that would look like for a day/year on 20 million units? (I don't want to upset the engineers on the board with my math)

Too hard to quantify because you'd have to figure in the energy cost of the organic PV layer and we have no data whatsoever on that. I will venture to guess that from a macro perspective this will be mostly irrelevant, it's not intended for green reasons - it's intended to extend portability.

Too hard to quantify because you'd have to figure in the energy cost of the organic PV layer and we have no data whatsoever on that. I will venture to guess that from a macro perspective this will be mostly irrelevant, it's not intended for green reasons - it's intended to extend portability.

Exactly - the total amount would never be above the actual usage of the device. If these devices use something on the order of 2.5W (and surely the iPhone uses way less than this), then they use less than your tiniest lightbulb, even if it isn't an incandescent one.

Exactly - the total amount would never be above the actual usage of the device. If these devices use something on the order of 2.5W (and surely the iPhone uses way less than this), then they use less than your tiniest lightbulb, even if it isn't an incandescent one.

Most probably he is. Don't mind that kind of shenanigan. Not worth the trouble.

Actually I was just making a joke about the fact that one of the few samsung fanboys in the world spends so much time posting here. Presumably because there aren't enough other samsung fanboys for any decent sites dedicated to them.

Actually I was just making a joke about the fact that one of the few samsung fanboys in the world spends so much time posting here. Presumably because there aren't enough other samsung fanboys for any decent sites dedicated to them.